In most cases, you can find out the sex of your baby about halfway during your pregnancy — between 16 and 20 weeks — during a structural ultrasound. But what if you want to know sooner?

There are many reasons why you might want to know sooner. You may want to get a head start decorating a nursery or registering for a baby shower.

Finding out early can also help you prepare if your baby might have a congenital or genetic disorder. Some disorders are linked to whether the baby is a boy or a girl. If your family has a genetic history of one of a particular disorder, you might be interested in finding out the sex as soon as possible.

Dr. Saam Ramzi Ismail developed the Ramzi theory. It’s also sometimes called Ramzi’s method or the Ramzi theory or method.

Dr. Ismail claims it can determine fetal sex by as early as 6 weeks into a pregnancy using a 2-D ultrasound. But just how sound is this theory?

According to this theory, Dr. Ismail tried to determine if there was a relationship between a baby’s sex and how and where the placenta formed. He did this by looking at the laterality of placental/chorionic villi. These are the hairlike formations that make up the placenta.

However, this method of determining sex hasn’t been confirmed by peer-reviewed research. A peer-reviewed journal is where established medical studies are published so their validity can be reviewed by other scientists and doctors.

Still, it’s become a very popular topic of discussion among women who are pregnant. Many women are posting screenshots from their early ultrasounds to see if anyone can guess their baby’s sex using the Ramzi theory.

Is there a scientific basis for the Ramzi theory? The short answer is no. There’ve been no further studies on using placenta placement to predict sex as early as 6 weeks. So, doctors remain skeptical.

“The Ramzi theory sounds too good to be true, as many point out. It may not have any real scientific validity,” said Dr. Sherry Ross, OB-GYN and women’s health expert at Providence Saint John’s Health Center in Santa Monica, California.

She also notes that the sex organs begin to form in an embryo at 4 weeks. “It would be really amazing to learn that someone could find out this information only two weeks later, with a 97 percent accuracy rate,” she said.

So, what’s the consensus?

“The important take-home message about the Ramzi theory is that couples should not make any premature decisions at 6 weeks about the fate of the embryo,” Dr. Ross said.

If you’re concerned about genetic abnormalities based on sex, use one of the accepted genetic tests.

The most accurate way of determining sex has always been through checking the chromosomes of the baby. This has traditionally been done through invasive tests, such chorionic villi sampling performed between 11 and 14 weeks, or amniocentesis performed at about 16 weeks.

There’s also a new, noninvasive maternal blood test that might determine a baby’s sex by as early as 9 weeks. This is cost-effective and not a risk to baby or maternal health.

The primary indication for performing this test is to provide information on the baby’s risk for chromosomal disorders, including Down syndrome. The test isn’t used as simply a sex determination test, unless there’s concern for sex-linked disorders.